Adverse Effects of Intermittent Fasting: Intermittent fasting can have many negative physical and mental consequences. These can range from feelings of extreme hunger to headaches, lightheadedness, digestive problems, mood changes, fatigue, low energy, and sleep disturbances.
This may lead to weight gain, digestive problems and the development of unhealthy eating habits. 16/8 intermittent fasting may also cause short-term negative side effects when you're first getting started, such as hunger, weakness and fatigue -- though these often subside once you get into a routine.
Some evidence suggests that a 16-hour fasting, 8-hour eating cycle may raise heart disease risk compared with other time-restricted eating cycles. Intermittent fasting also may cause people to feel very tired and dizzy. It can affect diabetes management and cause headaches or mood swings.
Potential Drawbacks of Intermittent Fasting
If you're not already used to skipping meals or not eating for an extended period of time, the hunger and fatigue that can occur when starting IF can be difficult to handle. Other side effects can include insomnia, irritability, headaches, and nausea.
Organ Systems Involved
The most immediate organ affected by a fast is the pancreas. During times of low plasma glucose, the pancreas will release more glucagon from the alpha cells found in the islets of Langerhans. Glucagon will mainly affect the liver as it stores most of the glycogen in the body.
The annual federal survey asks participants about their dietary patterns. After comparing the results to death data from the Centers for Disease Control and Prevention, the team concluded that intermittent fasting led to a 91% increased risk of death from cardiovascular disease.
If you are healthy and are not taking medication that affects your hydration, your kidneys should not be affected by careful fasting. Fasting can in the summer months be as long as 20 hours and some with underlying health conditions may not be able to fast for such long periods.
For example, studies have found that people who regularly fast more than 16 or 18 hours a day have a higher risk of gallstones. They're also more likely to need surgery to remove the gallbladder. Eating for 12 hours and then fasting for 12 hours is likely safe for most people, Longo explains.
According to the researchers' presentation (PDF, 373KB, 1 page), people who limited their eating window to less than eight hours a day had a 91 per cent (almost double) increased risk of dying from heart and circulatory diseases, compared to those who had a more typical eating window of 12 to 16 hours.
In conclusion, fasting impairs the urinary concentrating ability and, as a result, causes polyuria. This effect is mediated via suppression of AQP2 expression in the collecting duct.
Although some people find it easy to stick with this pattern over the long term, one research study that was not designed specifically to look at an intermittent fasting pattern found that limiting your daily time window of eating does not prevent weight gain over time or yield significant weight loss results.
Early fasting reduces amount of abdominal fat
The results demonstrate that time-restricted eating can be an effective strategy for reducing body weight, regardless of the timing of the eating window, offering flexibility for individuals to choose an approach that fits their lifestyle,” Ruiz said.
If you are fasting for weight loss or metabolic health, then coffee or even coffee with non-insulinogenic (insulin-spiking) additions like butter, coconut oil, or heavy cream should not break your fast. However, milk, flavored creamer, sugar, and many other sweeteners will break your fast, no matter your goals.
Most people who try intermittent fasting don't see much of a change in their poop, Julie Upton, RD, Health's registered dietician and writer, told Health. However, some people say they poop less frequently.
Adverse Effects of Intermittent Fasting: Intermittent fasting can have many negative physical and mental consequences. These can range from feelings of extreme hunger to headaches, lightheadedness, digestive problems, mood changes, fatigue, low energy, and sleep disturbances.
After fasting, your body needs gentle food options to ease back into digestion. Focus on hydrating, easy-to-digest foods — think light veggie soups, simple smoothies, or bland foods like rice or toast. Avoid foods that are high in fiber, fat, sugar, or spice.
Ideally, the association of fasting and lower blood pressure levels means a possible decrease in hypertension-related complications due to the reduction of the workload on the heart. However, the evidence supporting the direct impact of fasting on cleaner arteries is not conclusive.
One word of caution, though: Fasting can lead to an electrolyte imbalance. This can make the heart unstable and prone to arrhythmias. “So whenever we prescribe certain diets, including a very low calorie diet and protein-sparing modified fast diet, these require medical supervision.
"Intermittent fasting can have both positive and negative effects on liver health. While it may help reduce the risk of fatty liver disease and improve liver enzymes, it is important to approach this eating pattern with caution, particularly if you have pre-existing liver conditions.
While both 12-hour and 16-hour fasting can promote fat burning, it's possible that a 16-hour fast may be more effective. This is because the longer fasting period may lead to a greater depletion of glycogen stores, which can trigger higher levels of fat burning.
You may need a longer or shorter eating window, or you may want to try out a new protocol entirely. Decrease (or increase) your calorie intake within your fasting window. Aim for 7–9 hours of sleep. Cut back on processed foods.
Fasting depletes the liver's store of glucose, prompting fat cells to release fats. The fats travel to the liver where they're converted into ketones, which are essentially small pieces of fats that cells can use as an energy source.
Additionally, during fasting periods, since you're not eating, you may forget to drink water, promoting dehydration. Make sure to stay hydrated throughout your fasting periods, and monitor the color of your pee (urine) regularly. A pale yellow color is normal, whereas a dark color may indicate dehydration.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, research suggests that drinking lemon water may help prevent kidney stones. Not drinking enough water can increase the risk of kidney stones.